1. Field of the Invention
The subject invention relates to an automotive heating ventilation and air conditioning (HVAC) systems of the type, and more particularly to a door mechanism of the HVAC system, which can slide therein to control air flow.
2. Description of the Prior Art
Modern vehicles are designed to provide passengers with comfort, convenience, and safety. One comfort system that few could live without is an air conditioning system. The air conditioning system is used in the modern vehicles is designed to cool, dehumidify, clean, and circulate the air in a vehicle. The air conditioning system presents a closed, pressurized system that has a compressor, a condenser, a receiver/dehydrator (R/D), an expansion valve or orifice tube and a plurality of additional components, such as a box shaped housing, known as a heating, ventilation and air conditioning system (HVAC system). A heart of the HVAC system, used in combination therewith to increase efficiency and dependability of the air conditioning system, is a box shaped housing containing an evaporator and heater, which are spaced apart, with inner faces that face one another and outer faces that face away from one another. Such systems obviously require enough space between the evaporator and the heater for air mixing doors, positioned therebetween, to swing, limiting how compact the entire HVAC system can be made. In addition, the air mixing doors tend to lack linearity. That is, they tend to be all on, or all off, but are far less adept at attaining.
Alluding to the above, the HVAC systems permit occupants to select a desired temperature for their individual zones and automatically maintain these zones at the pre-selected temperature. Such operation necessarily requires the use and operation of multiple valves and ducts to achieve the desired operation of the HVAC system. While the sophistication and complexity of the HVAC system has steadily increased, the design of valves utilized in HVAC system has remained relatively unchanged throughout the years. The HVAC systems now include a number of separate valves that have been automated through the use of various types of actuators mounted exteriorly to the HVAC module and either connected to the valve directly or with mechanical linkages such as gears, push rods, or mechanical arms.
Various HVAC systems and designs are disclosed in the U.S. Pat. No. 4,899,809 to Takenaka et al.; U.S. Pat. No. 6,092,592 to Toyoshima et al.; U.S. Pat. No. 6,270,400 to Tsurushima et al.; U.S. Pat. No. 6,305,462 to Tsurushima et al.; U.S. Pat. No. 6,347,988 to Kurokawa et al.; U.S. Pat. No. 6,382,305 to Sano; U.S. Pat. No. 6,450,877 to Tsurushima et al.; U.S. Pat. No. 6,508,703 to Uemura et al.; U.S. Pat. No. 6,569,009 to Nishikawa et al.; U.S. Pat. Nos. 6,612,922 and 6,688,964 both to Uemura et al.
The U.S. Pat. No. 6,092,592 to Toyoshima et al., for example, teaches an HVAC unit for a vehicle having a temperature control system. A first air mixing door of the temperature control system is used for adjusting an opening degree of a cool air passage through which air having passed through an evaporator bypasses a beater core. A second air mixing door of the temperature control system is used for adjusting an opening degree of an air inlet portion of the heater core. The first and second air mixing doors include a rotation shaft at a center and connected to a housing to facilitate a butterfly-like rotation of the first and second doors to mix cool and hot air. The first and second mixing doors are substantially spaced from one another thereby diminishing packaging value of the air conditioning system.
The U.S. Pat. No. 6,305,462 to Tsurushima et al. teaches a door mechanism for an automotive air conditioning system. Unfortunately, the door mechanism taught by the U.S. Pat. No. 6,305,462 to Tsurushima et al. separates cold and hot air streams therefore without promoting mixing of the cold and hot air streams, which results in the need for various baffles and/or a mixing door to be added to achieve a desired temperature. Another example, taught by the U.S. Pat. No. 6,688,964 to Uemura et al. is a door mechanism, wherein a pair of door valves are formed from a polymeric film and are spaced from one another at a fixed distance.
There is a constant need in the area of an automotive heating ventilation and air conditioning (HVAC) system for a door mechanism, which will improve packaging characteristics of the HVAC system, improve mixing of cold and hot air streams to achieve a desired temperature to control air flow into the interior of the vehicle and to eliminate baffles or mixing doors.